THE SUBTITLE DESCRIBES THE book: "The Omagh Bombing and the Families' Pursuit of Justice". It is a remarkable and moving story, told in masterly fashion by Ruth Dudley Edwards. Her narrative grips from the start. It is as compelling as a thriller and displays the sympathetic imagination of a great novel.

On Saturday 15 August, 1998, a bomb placed in a parked car by the self-styled Real IRA exploded in the quiet town of Omagh as people went about their business, shopping and eating in restaurants. It killed unborn twins, six men, 12 women and 11 children. Among the children were two young Spaniards and an English boy, all on holiday. There was no particular target. Catholics, Protestants and a Mormon were indiscriminately murdered.

The atrocity seemed all the more outrageous because it came a few months after the Good Friday Agreement which had established what was called the peace process, at a time when people of both communities in Northern Ireland could at last hope that "the Troubles" were at an end, and could look forward with some optimism to a better future. The Real IRA, a group of hard-line Republicans, had broken away from the Provisional IRA/Sinn Fein because the decision to enter into negotiations with the British Government and the Ulster Unionists implied an acceptance of the Partition of Ireland. They hoped a renewed bombing campaign would destroy the peace process. They got it wrong. The wave of outrage on both sides of the Border unnerved them, and they soon tried to shift some of the responsibility to another dissident group, the Continuity IRA.

The reaction, either side of the Border, to the Omagh bomb demonstrated a commitment to the peace process; the Republican men and women of violence were further discredited. Nevertheless the Sinn Fein leaders, Gerry Adams and Martin McGuinness, couldn't bring themselves to call for co-operation with the police in their investigation. The most they would say was that the bombing was "unhelpful".

The criminal investigation moved very slowly. Although the police, in the Republic and in Northern Ireland, believed they knew who the murderers were, they could not find evidence sufficient to bring charges. It looked as if there would be no convictions and the killers would remain at liberty to bomb another day when the initial furore had died down.

At this point something truly remarkable happened. A group among the bereaved families refused to give up hope of seeing justice done. Led initially by an English solicitor, Victor Barker, and a motor mechanic, Michael Gallagher  both of whom had lost sons that day  they resolved to pursue the killers by every legal means possible. Not all the bereaved families were in agreement. Some understandably wanted to be left alone to rebuild their lives as best as possible, and felt the course taken by the Action Group was prolonging their agony. But Barker, Gallagher and their associates were determined not to give way. If there were to be no criminal charges, might it be possible to pursue the alleged murderers in the civil courts? This was daring, dangerous, and all but unprecedented. They had embarked on a long and arduous journey.

Ruth Dudley Edwards herself became involved in the campaign at an early date. A Dublin-born journalist and author, she had travelled some distance from her roots, in the course of which she had acquired sympathy for Ulster Protestants and had written a generous study of the Orange Order. She now found herself at the centre of a group committed to support of the Omagh families. Other members included Robert Cranborne, former Tory minister (now the Marquess of Salisbury), Lady Jane Dawnay, born a Grosvenor and brought up in Northern Ireland, previously married to the Duke of Roxburghe, and Sean O'Callaghan, a former IRA gunman, who had turned informer, done time in a British gaol, and was now among the most committed opponents of IRA violence.

This group devoted itself to raising money to finance legal action and to cooperating with lawyers in preparing a case. It was a long and tortuous business, and very often they were on the brink of failure. Press campaigns, vigorously supported by Paul Dacre, editor of the Daily Mail, and by the Daily Telegraph raised money. They sought and secured supporters in high places, among them the Prince of Wales (whose great-uncle and mentor, Lord Mountbatten, had been murdered by the IRA), and Peter Mandelson, whose many critics may be surprised to find that he comes out of this story very well, far better than any other politician. (Those who know that he was among the most successful of Northern Ireland Secretaries of State, and one who, unlike the late Mo Mowlam, kept Sinn Fein at arms' length, will not share this surprise.)

There were many setbacks. Lawyers for the accused employed delaying tactics which might have broken the resolution of people less determined to see justice done. But the tenacity of the Omagh families was remarkable, and it was eventually rewarded when the case came to court and judgment was given in their favour. Their extraordinary campaign has created a precedent. Even when there is insufficient evidence to convict people accused of terrorist activities in a criminal trial, this need not now be the end of the matter. They can be pursued in the civil courts where the establishment of guilt demands less positive proof, probability being sufficient.

This is an extraordinary and uplifting story of how a group of ordinary people managed to get the justice they sought. It is beautifully told.

In the first chapter, Ruth Dudley Edwards introduces us to the victims and their families, telling their life stories, recounting just what each did and suffered on 15 August, 1998. Through all the months and years which followed, through dark days when it seemed as if the attempt to see justice done must fail, we are never allowed to forget the dead, never permitted to escape the realisation of the pain and grief their families suffered.

We are called to admire the Omagh families and to share sympathetically in their struggle. We are reminded on almost every page of the wickedness of those who murder innocent people in pursuit of their political ideal.